There are several illnesses which can cause an obstruction in the flow of urine from the bladder. For instance, a common problem in the aging male is an enlarging prostate gland which obstructs lower tract urinary flow. A poor urinary stream can also result from a weak or diseased bladder.
A helpful tool in the detection of such illnesses is the study of urinary flow rates. While a urinary flow rate study can be used to recognize a symptom, it is non-specific and cannot distinguish between illnesses, for instance between bladder outlet obstruction and impaired bladder contraction. However, the urinary flow rate study is highly accurate in separating individuals having poor urinary streams from individuals having normal urinary flow.
A urinary flow study, also known as uroflowmetry, is the recording of urinary flow rates during the act of micturation. A flow rate of a volume of urine expelled via the urethra per unit of time is expressed in terms of cubic centimeters per second (cc/sec). The flow data provides a peak flow rate, often referred to as (Qmax) and an average flow rate. The peak flow rate is specifically useful since it can identify patients with bladder outlet obstructions. The uroflometry recordings of an individual patient can be compared with those of a normal healthy person's urinary flow. Of course, the flow rates are dependent upon bladder volume, patient's age, outflow obstruction and the degree of abdominal and bladder contractions.
As an example of the usefulness of a urinary flow study, studies have shown that for a urine volume of 200 cc, the average normal healthy male will have a peak flow rate of 19 cc/sec. Studies have also shown that for a urine volume of 200 cc, a peak flow rate of 11 cc/sec or lower would be indicative of an obstructed or poor urinary flow rate in 97% of patients. Therefore, the urinary flow rate study provides an important tool in the detection of such illnesses.
Urinary flow rate studies are also very useful in monitoring the progress of medical treatment. For instance, some illnesses can be treated through the use of drugs. The success, or lack thereof, of the treatment can be monitored by testing the patient's urinary flow rates throughout the period of treatment.
A urinary flow rate study normally requires a patient to make an appointment with a physician and to visit the physician's office to perform the study. The physician will generally have an expensive, complex machine which provides the physician with a printout of the urinary flow rate study after the patient has performed the act of micturation in the appropriate machinery. For instance, U.S. Pat. Nos. 5,176,148; 4,683,748; and 4,732,160 illustrate devices for measuring urinary flow.
The prior art instruments for measuring urinary flow have several drawbacks. One drawback is that the patient must make an appointment with the physician and visit the physician's office in order to perform the test. Therefore, the patient is inconvenienced not only by the expense, but also by having to take the time to visit the physician's office. Another drawback is that the test only represents a single measurement at a single point in time. A single urinary flow measurement may not be representative of the patient's true voiding pattern. In addition, the uncomfortable situation of having observers present while the patient is voiding may also cause the result to be less than representative of the patient's true voiding pattern. The patient in this environment is also more likely to strain his abdominal section or have an intermittent urine flow.
Devices for measuring urinary flow rates which are less complex are also known. For instance, see U.S. Pat. No. 4,099,412. Such devices still require a physician, or nurse, to "eyeball" the flow rate indicia located on the devices while the patient is voiding. These methods still have the drawback of providing only a single test at a single point in time and of placing the patient in a less than comfortable environment.
While the aforementioned devices provide the function of detecting urinary tract obstructions in a somewhat satisfactory manner, there is a need for a device which can be used by an individual at his place of residence to allow the individual to visually observe a good or poor urinary stream. The urinary flow testing device should be inexpensive and simple to use. The device, or a kit having a series of the devices, should allow an individual to test his urinary flow repeatedly over a period of time so that a representative measurement of his true voiding pattern can be obtained. The device being used at one's residence without the presence of other observers should allow the individual to void without the pressure of being in a physician's office with other people present.